Linux Today: Linux News On Internet Time.





More on LinuxToday


IBM alphaWorks Releases JDK for Linux, Source for JavaBeans

Jun 11, 1999, 21:00 (6 Talkback[s])

WEBINAR: On-Demand

No-Size-Fits-All! An Application-Down Approach for Your Cloud Transformation REGISTER >

Frank Carlos writes:

"IBM begins opening source for JavaBeans. Based on customer demand, a subset of IBM's award-winning JavaBeans are now available with source code. Downloaders can become members of the 'alphaBeans with Source' community."

"The release of the alpha version 1.1.6 of the IBM Developer Kit continues IBM's strong commitment to the Linux and Java platforms and communities. The Developer Kit is IBM's port of Sun's JDK(TM) 1.1.6 to the Linux operating system running on Intel architecture based computers. The Developer Kit includes similar IBM Just-In-Time (JIT) compiling technology found in IBM's high performing, industry-leading Developer Kits for the OS/2 and Windows** operating systems."

[ Here is the FAQ for the Linux JDK. -lt ed ]

1. On what Linux systems can I run the IBM Developer Kit?

A. We have tested it on: Caldera Open Linux 2.2 ®, Pacific Hi Tech TurboLinux 3.6 ®, RedHat Linux 6.0 ®, SuSE Linux 6.1 ®

Our expectation is this code will run on other Linux® products that include the code requirements below. We welcome your comments on our alphaWorks discussion forum to help us determine the other Linux distributions that run well with our alpha code.

This port requires:

  1. Linux kernel 2.2 (all Linux distributions above contain the 2.2 kernel) For information on upgrading your system with a 2.2.x level Linux kernel please see: http://www.kernel.org
  2. glibc 2.1 (Which ships with RedHat 6.0 and Caldera 2.2) You may also download glibc 2.1 from the ftp site at glibc.cygnus.com/pub/glibc
  3. LessTif 0.88.1 - you can download at no charge from www.lesstif.org b.) you may also replace LessTif with Motif 2.1 if you have a license for it

2. Why did you develop a Java 1.1.6 version Developer Kit?

A. Our goal was to get a high performance developer kit in your hands as quickly as possible. Using our 1.1.6 AIX port as a base provided us with an effective way to achieve that objective. Similarly, IBM's 1.1.6 JIT for Intel is proven technology that provided a solid starting point for porting to Linux.

2b. What kind of performance do you see with this code.

A. Our limited testing experience on the Linux platform indicates the code performs well. Please share your performance experience with this code on our discussion forum by clicking on the 'discussion button' .

3. What are the system requirements?

A.

Computer:      Intel 486 or better (Pentium recommended)
Platform:      Linux
Disk Space:    9MB    (to download) 30MB (to uncompress),
Memory:        32MB RAM
Display:       Suitable for X-Window usage
Dependencies:   Linux kernel 2.2, glibc 2.1, Motif ®/Lesstif 2.1

4. Where can I go for additional information on this alpha code?

A. You can access our discussion forum that has been established to collect your suggestions and ideas by clicking on the 'discussion button' at this site.

5. What Java programs are supported?

A. We are not supporting any programs with the alpha version of the code. This code is intended for your evaluation only. There is no support offered other than the alphaWorks discussion forum.

6. When will you make this a generally available product?

A. This is a technology offering. We have no specific plans at this time to make this a commercial product. We are very committed to the Linux platform and will continue to explore ways we can satisfy the needs of the Linux community.

7. How can I ask questions or get support for this alpha code?

A. As an alphaWorks technology, no support is offered for this code. We have established the discussion forum as a means for you to share ideas and helps among the user community.

8. How do I install the code?

A. Please refer to the README file and the download instructions available on alphaWorks for installation instructions.

9. How do I know if the code installed successfully?

A. You can run the 'java -fullversion' command to check whether or not your PATH is set correctly to access the IBM Developer Kit. The fullversion command will return a string that reports that the java you are running is level 1.1.6, built by IBM and will list a build date of the form l116-1999MMDD which shows the month and date of the build. If you do not see a string like this or the command generates an error, then you are not using the IBM Developer Kit. Please see the README for further troubleshooting instructions.

10. How do I uninstall the code?

A. To remove the code, you can perform two simple steps. If you have added the code to your path in your shell startup script, remove the bin directory of the Developer Kit from your PATH. After completing this step, go to the parent of the directory where you installed the Developer Kit and type 'rm -fR <javarootdir>' where <javarootdir> is the subdirectory name of your installation. For example, if you have installed the Developer Kit in /usr/ibm116, go to /usr and type 'rm -fR ibm116'. This will remove the code from your system.

11. Can I install and use this software alongside any existing Java TM developer kits?

A. Yes, you can. Simply install the IBM Developer Kit in a separate directory from any other developer kits and use the PATH variable to specify which one you wish to run. Instructions for doing this are addressed specifically in the README. Look there for further instructions.

12. How can I improve performance?

A. When running benchmarks or other memory intensive programs which may require large amounts of heap, use the -ms and -mx command line options to specify a heap size. For example, if you wish to set the Java heap size to 64MB, specify '-ms 64m -mx 64m' on the command line. By doing this, performance may be increased since the initial heap size is large enough such that heap expansion does not have to be performed in small increments up to the working set of the application.

13. I seem to run into problems trying to use more than around 200 threads. How can I increase the number of threads available to my Java application or applet?

A: Since the IBM Developer Kit for Linux uses native threads, the underlying architecture of Linux represents each thread as a process. The kernel specifies a maximum number of processes per user which creates a hard limit that is usually set to 256 tasks per user. Therefore, if you wish to run a Java application which requires more than 256 threads, you need to recompile the kernel with a higher maximum task limit. The header file which requires modification is located in the source tree of the kernel in include/linux/tasks.h. A constant is defined in this file called NR_TASKS, which is normally 512, but can be set as high as 4092 on Intel Linux systems. Also, another definition in the same file is MAX_TASKS_PER_USER which is defined as NR_TASKS/2. This can be changed if you want non-root users to be able to create more processes (or threads in our case) than half of the entire system maximum. After changing these definitions you must recompile the kernel. For information on kernel-specific issues, you can check the main Linux kernel web site at http://www.kernel.org.

14. Where can I find a list of known problems with the alpha code?

A. Please look in the README file that is packaged with the software to find a list of known problems with this alpha release. We would be interested to learn of any problems you discover with the alpha code in our discussion forum.

15. Will IBM make the source code available for the IBM Developer Kit for Linux® , Java TM Technology Edition, alphaVersion 1.1.6?

A. IBM does not have the rights to provide the source code for this Developer Kit.

16. Where can I find more information about Java and Java TM2 offerings from IBM?

A. Please access the IBM web site at: www.ibm.com/java

IBM, and alphaWorks are registered trademarks of International Business Machines Corporation.
** Java and all Java-based marks are trademarks or registered trademarks of Sun Microsystems, Inc. in the U.S. and other countries.
*** All other company names may be trademarks or registered trademarks.